Each cycle, my goal as a handicapper is to identify Congressional races where the result will mean a partisan takeover, not merely where the outcome will be close.

To some, this may seem like an odd distinction. After all, if an election is close — within a few points — doesn’t that also mean that the seat potentially could flip from one party to the other?

For most races, of course, the answer is “yes,” but not for all. The best example of it this cycle may well be Florida’s 2nd district, in the state’s panhandle.

The 2004 and 2008 presidential results in the district were close, so freshman Rep. Steve Southerland (R) can’t take his re-election completely for granted. And yet, while a new Democratic poll showed Southerland and challenger Al Lawson (D) in a dead heat (as did two before it), it’s hard to imagine Lawson winning in November.

That conclusion shouldn’t be seen as a criticism of Lawson, a former college basketball player who played briefly in the pros before serving years in the Florida House and Senate. He is personable and likable, and he knocked off a favored state legislator in the Democratic Congressional primary this year.

Nor am I disputing the accuracy of pollster Ron Lester’s survey, which showed Lawson and Southerland tied at 43 percent in the ballot test and 47 percent after “positive” paragraphs about the two men were read to respondents. It’s simply that, in this case, the poll has little predictive value.

Southerland is likely to win re-election with somewhere from 51 percent to 53 percent of the vote, and that assessment is based on the makeup of the district, which, I believe, augurs well for both a close outcome and a Southerland victory next month. And that’s why I have resisted moving the race to a more competitive category.

Florida’s 2nd district is really two districts in one.

Leon County (Tallahassee) is home to a large black population, a large number of colleges and universities, and the same kind of liberals who have been drawn to Asheville, N.C.; Austin, Texas; and Madison, Wis. The rest of the district is filled with conservative whites, who have a very different view of the two parties and of the role of government.

Leon County gave Barack Obama more than 61 percent of the vote in 2008, but he lost the 2nd district by 9 points, 54 percent to 45 percent. That means he got absolutely clobbered in the non-Leon County portion of the district.

Of course, redistricting has changed the district’s boundaries slightly, improving its Democratic performance. Obama received 47.83 percent of the vote in the redrawn district, while 2004 presidential nominee Sen. John Kerry (D) received 46.97 percent. Sen. John McCain (R) won the redrawn district with 51.94 percent, while George W. Bush carried it with 51.48 percent when he was re-elected.

Those numbers are unusual and very telling.

The Democratic and Republican votes in both elections were remarkably consistent. Most districts that Bush carried with 51 percent went for Obama four years later, but not this one. Why not?

Voters in this district are incredibly polarized. It’s unlikely that 51 percent of the voters in this district would vote for any liberal Democrat, while close to 47 percent of district voters will always vote for the Democrat, no matter who he or she is.

The 2nd is the only district in Florida where McCain ran measurably better than Bush. And it is one of a relatively few districts in the nation where that happened.

McCain ran ahead of Bush in a swath of districts stretching from western Pennsylvania and West Virginia down through eastern Tennessee, eastern Kentucky and parts of the Deep South, then all the way to Oklahoma and eastern Texas.

Some of these districts have substantial black populations, but others don’t. What they all have in common is large numbers of extremely conservative, white voters who didn’t like Obama and have turned strongly against his party in recent years.

Now, ask yourself, if Obama got less than 48 percent of the vote in Florida’s 2nd district in 2008, is he going to get more than that next month? Even if he does, is he going to carry the district? And if Obama can’t carry the district, how is Lawson going to in a presidential year?

Lawson, an African-American Democrat whose website shows few differences from the national party on issues, will have a hard time appealing to conservative white voters who will see him as another Obama supporter, just as the conservative Southerland will have a hard time getting the votes of white liberals and black voters who will regard him as an opponent of Obama and the Democratic agenda.

That’s why the Democratic primary was so important, and that’s why national Democratic strategists were counting on state Rep. Leonard Bembry, who had been endorsed by the Blue Dogs, to win their party’s nomination. A moderate white Democratic candidate might be able to attract a handful of conservative voters, maybe enough to win.

Sen. Bill Nelson, a white Democrat who runs as a moderate — his website lists reducing the federal deficit, cutting spending and “fixing” the health care law as priorities — is at 49 percent on the Senate ballot in the Lester poll of 2nd district voters. He does have a good chance of carrying the district against a weak GOP Senate nominee.

Lawson’s vote is likely to track with the president’s in the district. The Lester survey showed Obama getting 46 percent, a point less than Mitt Romney. But Romney will win the district, as McCain and Bush did.

So, I don’t have trouble accepting the Lester poll or other private Democratic surveys showing Lawson running even with Southerland in the mid-40s. But Lawson’s problem is that he is starting to bump up against his ceiling. He will need to get half of the votes cast in the district, and he can’t get there next month.

Given that, while some observers look at Lester’s poll and see a possible Lawson victory, all I see is a candidate getting his base vote — a vote that, because of the district’s makeup, will fall a few points short of what he needs.